Effect of insulin antibodies on free and total plasma-insulin.

Insulin administration often causes the development of insulin antibodies. Plasma insulin-binding capacity was assessed and free and total plasma insulin were measured in 96 insulin-dependent diabetic patients. Patients with the highest insulin binding capacity not only had the highest total insulin but also had the lowest free insulin. It is concluded that bound insulin is not unavailable to cells, that sufficient dissociation can occur for this insulin source to make a sizeable contribution to insulin delivery to the cell receptors, and that this can happen at a very low free insulin concentration.